The invention relates generally to generating representations of a three-dimensional object on a computer screen, and more particularly to a system for modeling the surface of a three-dimensional object using data generated by a surface contour sensing system.
Systems and methods for generating two-dimensional information about a three dimensional object are well known. These well known two-dimensional systems typically use a flat table that has a touch sensitive surface. To generate data for a particular point, a stylus is used to depress the touch-sensitive surface and cause electrical signals to be generated relating to the position of the stylus on the table. These stylus position signals may be used to generate two-dimensional data about the object. These two-dimensional digitizing systems, however, are not suitable for generating data about the surface of three-dimensional objects.
Systems and methods for generating three-dimensional data about an object and for displaying a representation of the object on a computer screen are also well known for such applications as computer aided drafting and machining (CAD/CAM), medical analysis and visualization, and modeling of objects. These well known three-dimensional data generation devices may include either a mechanical probe coordinate measuring machine (CMM), or an optical system. The CMM systems generally use a type of electromechanical probe to contact and follow the surface of the object and generate data relating to the surface of the object along the scan line. The data generation process is repeated for successive scan lines until data is gathered for the entire object. These mechanical probe systems are slow and require expensive, complex, large machines, and require a large amount of processing power to control the mechanical probe and process the scan-line data.
The known optical systems typically use incandescent light or laser light to generate data relating to the surface of the object. In one optical system, light is projected towards the object and the reflected light from the surface of the object is received by a sensor. In another optical system, a video camera is used to form images of an object at various different angles to generate data about the surface of the object. These optical systems can generate data concurrently for a large portion of the object so that the time necessary to generate data for the entire object is reduced. These optical systems, however, are susceptible to misalignment problems that can corrupt the generated data. In addition, these optical systems are expensive, large machines that must be operated by a trained person.
All of these known three-dimensional sensing systems require a system for taking the generated three dimensional data and for generating a model of the surface contour of the three dimensional object. There are a number of known modeling systems that may be used with these sensing system. These known modeling systems are difficult for the average person to use because they are so complex. In addition, these known modeling systems also normally require the processing power of a work station or a high end personal computer, and are very expensive to purchase.
Some of these conventional modeling systems provide some capability for placing a texture map onto a three dimensional object. These conventional texture mapping systems map textures, such as a wood grain or a color, that do not have any specific features, onto a surface of an object. These conventional texture mapping systems cannot map a texture having distinct features, such as a picture of a face, onto a three dimensional model of a human head because these systems cannot handle positioning the texture map sufficiently accurately. In a conventional modeling system, any mapping of a texture with distinct features would be done by hand.
Thus, there is a need for a system and method for modeling the surface of a three dimensional object which avoid these and other problems of known devices, and it is to these ends that the present invention is directed.